He then goes on to show that a march to join the English army would involve a temporary renunciation of the Prussian base of operations.
These are the reasons he gives. He adds most unexpectedly:—[333]
“It is then evident that the Prussians decided on accepting battle because the Duke of Wellington had given them his word.” But of any such fact as this no mention whatever is made until the writer has occasion to speak[334] of the conversation between Wellington and Blücher between 1 and 2 P.M., when the French were deploying their columns for the attack. It is impossible to believe that Blücher had not before this made up his mind to fight, altogether independently of anything Wellington might say to him.
Ollech[335] suggests, as an answer to the question, “Why did Blücher give battle on the 16th although a whole army corps had not arrived?” that he did it in order to give the English army time to concentrate. This writer does not pretend that Wellington gave the Field Marshal any definite promise of support.[336]
Delbrück, in his Life of Gneisenau, says[337] that Blücher, relying on Wellington’s promise, and still hoping that at least late in the evening a portion of the IVth Corps would arrive, concluded to give battle.
There is really not much to be said on this subject. The truth is plain enough. Blücher had, as we have said above,[338] long ago fixed upon Sombreffe as the point of concentration for his army in case the French should cross the Sambre at or near Charleroi; and he had, most likely, communicated this determination to the Duke of Wellington. In arriving at this determination he undoubtedly assumed that he would be able to collect his whole army together,—say, 120,000 men. He thought, and he had a right to think, that if Napoleon should advance by way of Charleroi, he would be sure to attack the Prussian army if it should be found posted at or south of Sombreffe; and that Napoleon would be obliged to employ against it the bulk of his army. Hence Blücher calculated that the Anglo-Dutch concentration could be effected without serious molestation, and that some assistance at any rate from that quarter might safely be counted on. But when the day arrived, he found that he could not reckon on the arrival of one of his corps in time for the battle. Yet he still adhered to his determination to accept the contest, partly from unwillingness to retreat at the outset of the campaign, and partly in the hope that important aid would be received from Wellington. This determination, however, was arrived at without consultation with Wellington and before his letter was received,—in which, it is to be noted, there is no promise whatever,—and, of course, before the Duke himself rode over to Brye. What Wellington said no doubt strengthened the Field Marshal in his belief in the soundness of his decision; it reinforced his judgment; it gave him hopes of victory. But to say that his decision to receive the attack of the French at Ligny was based upon any promise of support made by Wellington, is entirely contrary to the evidence.